Unable to save entire recording. Disk audio may be full

All the suggested solutions on the web have been tried.
 
I am attempting to record a short 5 second passage. I am looping it because I need a bunch of takes. It won't get through the loop even one time before I receive the error. 
 
Project consists of about 30-40 audio tracks. All synths have been disconnected. 
 
1. Audio disk has 26 Gb free
2. Picture cache has been moved to another physical drive
3. Disk is defragmented weekly. I analyzed it again and it is 0% fragmented
4. I hit "E" to turn off all effects.
5. DiskRecBufferSize seems to be deprecated, but in Preferences/MIDI/Playback and Recording I found a Number of Buffers setting under Record. The max for this is 128, which I set it to. No idea if this is at all related.
6. CPU usage is very low (<10%) according to the Performance Module, even while attempting to record
7. Memory usage is about 27%
 
None of this has made the slightest difference. What else ya got?